Recently, with development of science and technology, portable electronic devices, such as video cameras, laptop personal computers, portable DVDs and personal digital assistants are becoming increasingly popular in people's daily life. As a desirable power source for portable electronic devices, lithium ion batteries are widely used due to high energy density, high working voltage and long life span. At present, lithium ion batteries have gradually substituted other traditional batteries and have been widely used in aircrafts, vehicles and medical equipments.
Generally, a lithium ion battery typically includes a battery can, a battery cell received in the battery can, electrolyte filled in the battery can and a battery cover sealing the battery can. In the prior art, the battery cover is typically assembled to the battery can via laser soldering for sealing the same. However, sealing the battery can and the battery cover via laser welding has the following disadvantages. The battery cover cannot be soldered onto the battery can via laser soldering quickly and the production efficiency is undesirable. At the same time, in the laser soldering procedure, defects may be introduced into the soldering area, especially when the battery cover does not tightly contact the battery can or when impurity is introduced at the soldering area, which may adversely affect sealing performance of the lithium ion battery.
What is needed, therefore, is to provide a lithium ion battery which has desirable sealing performance and can be assembled quickly.